U.S. patent application number 14/412751 was filed with the patent office on 2015-06-04 for display device equipped with power generation function.
This patent application is currently assigned to Sharp Kabushiki Kaisha. The applicant listed for this patent is Sharp Kabushiki Kaisha. Invention is credited to Makoto Eguchi.
Application Number | 20150154923 14/412751 |
Document ID | / |
Family ID | 49997155 |
Filed Date | 2015-06-04 |
United States Patent
Application |
20150154923 |
Kind Code |
A1 |
Eguchi; Makoto |
June 4, 2015 |
DISPLAY DEVICE EQUIPPED WITH POWER GENERATION FUNCTION
Abstract
An MEMS shutter-type display device equipped with a power
generation function, which achieves reduction of power consumption,
is provided in the present invention. The display device equipped
with a power generation function according to the present invention
includes: a first substrate including a movable first shutter with
a first slit, a first electrode, and a second electrode that is
installed on the side opposite to the first electrode via the first
shutter; a second substrate including a second shutter with a
second slit; a drive circuit to actuate the first shutter; the
first shutter being positively or negatively charged; and the drive
circuit being connected to the first electrode.
Inventors: |
Eguchi; Makoto; (Osaka-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sharp Kabushiki Kaisha |
Osaka-shi, Osaka |
|
JP |
|
|
Assignee: |
Sharp Kabushiki Kaisha
Osaka-shi, Osaka
JP
|
Family ID: |
49997155 |
Appl. No.: |
14/412751 |
Filed: |
July 17, 2013 |
PCT Filed: |
July 17, 2013 |
PCT NO: |
PCT/JP2013/069341 |
371 Date: |
January 5, 2015 |
Current U.S.
Class: |
345/212 ;
345/109 |
Current CPC
Class: |
G09G 3/3433 20130101;
G09G 3/20 20130101; G09G 2300/08 20130101; G02B 26/02 20130101;
H02N 1/008 20130101; G09G 2330/023 20130101; G09G 2330/021
20130101 |
International
Class: |
G09G 3/34 20060101
G09G003/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2012 |
JP |
2012-164198 |
Claims
1. A display device equipped with a power generation function
comprising: a first substrate including a movable first shutter
with a first slit, a first electrode, and a second electrode that
is installed on the side opposite to the first electrode via the
first shutter; a second substrate including a second shutter with a
second slit; a drive circuit to actuate the first shutter; the
first shutter being positively or negatively charged; and the drive
circuit being connected to the first electrode.
2. The display device equipped with a power generation function
according to claim 1, wherein the longitudinal direction of the
first slit and the longitudinal direction of the second slit are in
parallel with each other.
3. The display device equipped with a power generation function
according to claim 1 or 2, wherein the first shutter is moved with
the aid of an electrostatic force generated between the first
shutter and the first electrode.
4. The display device equipped with a power generation function
according to claim 1, wherein electrostatic induction caused by the
movement of the first shutter generates an electromotive force on
the second electrode.
5. The display device equipped with a power generation function
according to claim 1, wherein the second electrode is connected to
the drive circuit.
6. The display device equipped with a power generation function
according to claim 5, further comprising a rectifier circuit
between the second electrode and the drive circuit.
7. The display device equipped with a power generation function
according to claim 1, further comprising a light source, wherein
the amount of the light emitted from the light source and passing
through the display device is adjusted by the first shutter and the
second shutter.
8. The display device equipped with a power generation function
according to claim 7, wherein the second electrode is connected to
the light source.
9. The display device equipped with a power generation function
according to claim 8, further comprising a rectifier circuit
between the second electrode and the light source.
10. The display device equipped with a power generation function
according to claim 1, further comprising an external battery,
wherein the second electrode is connected to the external
battery.
11. The display device equipped with a power generation function
according to claim 10, wherein the second electrode and the
external battery are connected in series, and the display device
equipped with a power generation function further comprises a
rectifier circuit between the second electrode and the external
battery.
12. The display device equipped with a power generation function
according to claim 5, further comprising an external battery,
wherein the second electrode and the external battery are connected
in series, the external battery is connected to the drive circuit,
and the external battery is a secondary battery.
13. The display device equipped with a power generation function
according to claim 7, further comprising an external battery,
wherein the second electrode and the external battery are connected
in series, the external battery is connected to the light source,
and the external battery is a secondary battery.
14. A display device equipped with a power generation function
comprising: a first substrate including a movable first shutter
with a first slit, and a first electrode; a second substrate
including a second shutter with a second slit; a drive circuit to
actuate the first shutter; the first shutter being positively or
negatively charged; the second shutter doubling as a second
electrode; and the drive circuit being connected to the first
electrode.
15-26. (canceled)
27. A display device equipped with a power generation function
comprising: a first substrate including a movable first shutter
with a first slit, a first electrode, and a second electrode that
is installed on the side opposite to the first electrode via the
first shutter; a second substrate including a second shutter with a
second slit; a drive circuit to actuate the first shutter; the
first shutter being positively or negatively charged; the second
shutter doubling as a third electrode; and the drive circuit being
connected to the first electrode.
28-41. (canceled)
Description
TECHNICAL FIELD
[0001] The present invention relates to a display device equipped
with a power generation function. More specifically, the present
invention relates to a shutter display which utilizes an MEMS
(Micro Electro-Mechanical System) technique.
BACKGROUND ART
[0002] The MEMS technique has attracted much attention nowadays as
a technique for producing fine electronic parts. For example, it
has been studied to apply the MEMS technique to various electronic
devices such as displays, power generation devices, and so forth
(For example, see patent literature 1 or 2).
[0003] Examples of displays manufactured using the MEMS technique
include MEMS shutter displays. The MEMS shutter display includes a
very small shutter, which has been produced by the MEMS technique,
for each pixel. The display is turned on or turned off by opening
or closing the shutter to control the transmittance of light from
the backlight or the like. The display device has some advantages,
such as high efficiency of light utilization and low power
consumption, due to the unnecessity of the polarizing plate, color
filters, and so on, which are necessary for currently popular
liquid crystal display devices.
CITATION LIST
Patent Literatures
[0004] Patent literature 1: US 2006/0250325 A
[0005] Patent literature 2: JP 2011-36089 A
SUMMARY OF INVENTION
Technical Problem
[0006] MEMS shutter displays are low in power consumption compared
with liquid crystal displays. However, there is a room for more
consideration to reduce power consumption in the MEMS shutter
display.
[0007] Further, MEMS shutter displays and liquid crystal displays
are common in that they both consume electric power. Thus, they
both need external batteries or power generation devices to supply
electric power to drive the displays.
[0008] The present invention has been made in view of the above
state of the art. That is, it is an object of the present invention
to provide an MEMS shutter-type display device equipped with a
power generation function. The device can achieve reduction of
power consumption and has a power generation function.
Solution to Problem
[0009] The present inventor has studied for searching a method to
reduce power consumption of MEMS shutter displays, and focused on
the driving principle of the display. The display performs a
display by opening and closing the shutter at a high speed, and
power consumption required for driving the shutter appears to be
difficult to reduce. Thus, the present inventor has studied on
another approach to reduce power consumption.
[0010] The present inventor has paid attention on the points that
the shutter of the display is positively or negatively charged, and
that the display performs a display by sliding the shutter from
side to side. Also, he has found that electricity can be generated
by utilizing the movement of the shutter.
[0011] Specifically, the present inventor has found a structure in
which an electrode for generating electricity is installed at a
position opposite to the shutter at a given interval. The present
inventor has found that such a structure causes electrostatic
induction when the shutter approaches the electrode for generating
electricity when preforming the display, whereby the electrode for
generating electricity is charged reversely to the polarity to the
shutter. The present inventor has also found that the amount of the
electric charge on the electrode for generating power electricity
changes as the variation in the distance between the electrode for
generating electricity and the shutter according to the movement of
the shutter. Further, he has found that the electric current
produced depending on the amount of the change of the electric
charge can be taken from the electrode for generating electricity
and be reused.
[0012] The above constitution enables utilization of the shutter
drive not only for a display device, but also as a power generation
mechanism. The electromotive force generated can be used, for
example, for a part of a power source in the drive circuit. The
power consumption can therefore be reduced as a whole display.
[0013] Thus, the present inventor can successfully solve the above
problems, and has completed the present invention.
[0014] That is, an aspect of the present invention relates to a
display device equipped with a power generation function
(hereinafter also referred to as a first display device according
to the present invention) including: a first substrate including a
movable first shutter with a first slit, a first electrode, and a
second electrode that is installed on the side opposite to the
first electrode via the first shutter; a second substrate including
a second shutter with a second slit; a drive circuit to actuate the
first shutter; the first shutter being positively or negatively
charged; and the drive circuit being connected to the first
electrode.
[0015] The display device includes a first substrate and a second
substrate. The first substrate includes a first shutter with a
first slit, and the second substrate includes a second shutter with
a second slit. The first shutter is movable, and is positively or
negatively charged. Examples of the first shutter include
electrets. The "electret" is intended to mean a dielectric which is
permanently charged. The operation for charging a dielectric is
called "electretization". In the display device, transmission and
shielding of light from a light source is controlled according to
the degree of overlapping between the first slit and the second
slit.
[0016] The display device includes a first electrode and a second
electrode. The first electrode is a site which is connected to the
drive circuit, and at which a given electric potential is to be
received. The first electrode serves to actuate the movable first
shutter. The second electrode is used to supply a new electromotive
force to the power source by utilizing the transfer of electric
charges which is generated by the movement of the first
shutter.
[0017] A specific example is described. When the first shutter is
negatively charged, negative electrical potential, which has been
supplied from the drive circuit to the first electrode, causes an
electrostatic force (Coulomb's force) as a repulsive force between
the first electrode and the shutter. The repulsive force moves the
shutter in such a direction that the shutter slides away from the
first electrode. Here, the first shutter approaches the second
electrode, which is installed with the first shutter at a given
interval. This approach causes electrostatic induction, and
positive charges thus gather on the second electrode, causing the
transfer of electric charges (generating an electric current).
Then, when the polarity of the electric potential which is supplied
from the drive circuit to the first electrode is switched, the
first shutter returns to the original position by a restoring force
of an elastic body. Here, the movement of the first shutter to be
away from the second electrode causes electrostatic induction on
the second electrode. As a result, negative charges gather on the
second electrode, causing the transfer of electric charges
(generating an electric current).
[0018] When the first shutter is positively charged, negative
electrical potential, which has been supplied from the drive
circuit to the first electrode, causes an electrostatic force
(Coulomb's force) as an attractive force between the first
electrode and the shutter. The attractive force moves the shutter
in such a direction that the shutter approaches the first
electrode. Here, the first shutter slides away from the second
electrode, which is installed with the first shutter at a given
interval. This movement causes electrostatic induction, and thus
positive charges gather on the second electrode, causing the
transfer of electric charge (generating an electric current). Then,
when the polarity of the electric potential which is supplied from
the drive circuit to the first electrode is switched, the first
shutter returns to the original position by a restoring force of an
elastic body. Here, the first shutter approaches the second
electrode. This approach causes electrostatic induction on the
second electrode, and thus, negative charges gather on the second
electrode, causing the transfer of electric charge (generating an
electric current).
[0019] The configuration of the first display device according to
the present invention is not particularly limited as long as it
essentially includes such components. Thus, other components which
may be commonly used in the other display device may be
appropriately applied to the configuration.
[0020] The longitudinal direction of the first slit and the
longitudinal direction of the second slit are preferably in
parallel with each other. The shapes and the dimensions of the
first slit and the second slit are not particularly limited as long
as they are arranged such that the longitudinal directions of them
should be in parallel with each other.
[0021] To summarize the above, it is preferred that the first
shutter is moved with the aid of an electrostatic force generated
between the first shutter and the first electrode. It is also
preferred that electrostatic induction caused by the movement of
the first shutter generates an electromotive force on the second
electrode.
[0022] The second electrode is connected, for example, to the drive
circuit. This enables the supply of the electromotive force
generated on the second electrode to a power source in the drive
circuit.
[0023] When the second electrode is connected to the drive circuit,
it is preferred that the display device equipped with a power
generation function further includes a rectifier circuit between
the second electrode and the drive circuit. This enables an
efficient supply of the electromotive force to the power source in
the drive circuit since the rectifier circuit converts the
electromotive force from alternating current to direct current.
[0024] The display device equipped with a power generation function
may further include a light source. Displaying is controlled by
adjusting the amount of the light emitted from the light source and
passing through the display device by the first shutter and the
second shutter. The second electrode may be connected to the light
source. This enables supply of the electromotive force which is
generated on the second electrode to the light source.
[0025] When the second electrode is connected to the light source,
it is preferred that the display device equipped with a power
generation function further includes a rectifier circuit between
the second electrode and the light source. This enables an
efficient supply of the electromotive force to the light source
since the rectifier circuit converts the electromotive force from
alternating current to direct current.
[0026] The display device equipped with a power generation function
may further include an external battery. The second electrode may
be connected to the external battery.
[0027] It is preferred that the second electrode and the external
battery are connected in series, the external battery is connected
to the drive circuit and/or the light source, and the external
battery is a secondary battery. This configuration enables
accumulation of the generated electromotive force in the secondary
battery with the aid of the vibration from the outside of the
display device (environmental vibration) even when the display
device is turned off. Thus, it is possible to drive a display
device without any power generation device for electric power
supply.
[0028] When the second electrode and the external battery are
connected in series, it is preferred that the display device
equipped with a power generation function further includes a
rectifier circuit between the second electrode and the external
battery. This enables an efficient supply of the electromotive
force which is generated on the second electrode to the power
source.
[0029] According to the present invention, the above effect is
similarly achieved even when the second shutter doubles as the
second electrode.
[0030] That is, another aspect of the present invention relates to
a display device equipped with a power generation function
(hereinafter also referred to as a second display device according
to the present invention) including: a first substrate including a
movable first shutter with a first slit, and a first electrode; a
second substrate including a second shutter with a second slit; a
drive circuit to actuate the first shutter; the first shutter being
positively or negatively charged; the second shutter doubling as a
second electrode; and the drive circuit being connected to the
first electrode.
[0031] The configuration of the second display device according to
the present invention is not particularly limited as long as it
essentially includes such components. Thus, other components which
may be commonly used in the other display device may be
appropriately applied to the configuration.
[0032] Examples of the preferred modes of the second display device
according to the present invention include the same modes which
were described above as preferred modes of the first display device
according to the present invention. That is, the preferred modes of
the second display device according to the present invention
include the following modes:
(a) A mode in which the longitudinal direction of the first slit
and the longitudinal direction of the second slit are in parallel
with each other; (b) A mode in which the first shutter is moved
with the aid of an electrostatic force generated between the first
shutter and the first electrode; (c) A mode in which electrostatic
induction caused by the movement of the first shutter generates an
electromotive force on the second electrode; (d) A mode in which
the second electrode is connected to the drive circuit; (e) A mode
in which the display device equipped with a power generation
function further includes a rectifier circuit between the second
electrode and the drive circuit; (f) A mode in which the display
device equipped with a power generation function further includes a
light source, and the amount of the light emitted from the light
source and passing through the display device is adjusted by the
first shutter and the second shutter; (g) A mode in which the
second electrode is connected to the light source; (h) A mode in
which the display device equipped with a power generation function
further includes a rectifier circuit between the second electrode
and the light source; (i) A mode in which the display device
equipped with a power generation function further includes an
external battery, and the second electrode is connected to the
external battery; (j) A mode in which the second electrode and the
external battery are connected in series, and the display device
equipped with a power generation function further includes a
rectifier circuit between the second electrode and the external
battery; and (k) A mode in which the second electrode and the
external battery are connected in series, the external battery is
connected to the drive circuit and/or the light source, and the
external battery is a secondary battery.
[0033] According to the present invention, the above effect is
similarly achieved even when a third electrode is installed in
addition to the second electrode. Installation of such double
electrodes enables the supply of the electromotive force to both
the drive circuit and the light source respectively via
corresponding circuits, for example.
[0034] That is, still another aspect of the present invention
relates to a display device equipped with a power generation
function (hereinafter also referred to as a third display device
according to the present invention) including: a first substrate
including a movable first shutter with a first slit, a first
electrode, and a second electrode that is installed on the side
opposite to the first electrode via the first shutter; a second
substrate including a second shutter with a second slit; a drive
circuit to actuate the first shutter; the first shutter being
positively or negatively charged; the second shutter doubling as a
third electrode; and the drive circuit being connected to the first
electrode.
[0035] The third electrode is used, for example, to supply a new
electromotive force to the power source in the drive circuit by
utilizing the transfer of electric charges which is caused by the
movement of the first shutter in the same manner as the second
electrode.
[0036] The configuration of the third display device according to
the present invention is not particularly limited as long as it
essentially includes such components. Thus, other components which
may be commonly used in the other display device may be
appropriately applied to the configuration.
[0037] Examples of the preferred modes of the third display device
according to the present invention include the same modes which
were described above as preferred modes of the first display device
according to the present invention. That is, the preferred modes of
the third display device according to the present invention include
the following modes:
(l) A mode in which the longitudinal direction of the first slit
and the longitudinal direction of the second slit are in parallel
with each other; (m) A mode in which the first shutter is moved
with the aid of an electrostatic force generated between the first
shutter and the first electrode; (n) A mode in which electrostatic
induction caused by the movement of the first shutter generates an
electromotive force on the second electrode and the third
electrode; (o) A mode in which at least one of the second electrode
and the third electrode is connected to the drive circuit; (p) A
mode in which the display device equipped with a power generation
function further includes a rectifier circuit between the second
electrode and the drive circuit, and further includes another
rectifier circuit between the third electrode and the drive
circuit; (q) A mode in which the display device equipped with a
power generation function further includes a light source, and the
amount of the light emitted from the light source and passing
through the display device is adjusted by the first shutter and the
second shutter; (r) A mode in which at least one of the second
electrode and the third electrode is connected to the light source;
(s) A mode in which the display device equipped with a power
generation function further includes a rectifier circuit between
the second electrode and the light source, and further includes
another rectifier circuit between the third electrode and the light
source; (t) A mode in which the display device equipped with a
power generation function further includes an external battery
(hereinafter also referred to as a first external battery), and the
second electrode is connected to the first external battery; (u) A
mode in which the display device equipped with a power generation
function further includes an external battery (hereinafter also
referred to as a second external battery), and the third electrode
is connected to the second external battery; (v) A mode in which
the second electrode and the first external battery are connected
in series, and the display device equipped with a power generation
function further includes a rectifier circuit between the second
electrode and the first external battery; (w) A mode in which the
third electrode and the second external battery are connected in
series, and the display device equipped with a power generation
function further includes a rectifier circuit between the third
electrode and the second external battery; and (x) A mode in which
the display device equipped with a power generation function
further includes an external battery (hereinafter also referred to
as a third external battery), the second electrode and the third
electrode are connected in parallel, the second and third
electrodes and the third external battery are connected in series,
the third external battery is connected to the drive circuit and/or
the light source, and the third external battery is a secondary
battery.
Advantageous Effects of Invention
[0038] According to the present invention, an MEMS shutter-type
display device equipped with a power generation function, which
achieves reduction of power consumption, is provided.
BRIEF DESCRIPTION OF DRAWINGS
[0039] FIG. 1 is a schematic sectional view of one pixel in a
display device according to the Embodiment 1.
[0040] FIG. 2 is a schematic perspective view of one pixel of a
first substrate which is illustrated in FIG. 1.
[0041] FIG. 3 is a schematic perspective view of one pixel of a
second substrate which is illustrated in FIG. 1.
[0042] FIG. 4 is a view of a drive circuit in the display device
according to the Embodiment 1.
[0043] FIG. 5 is a schematic sectional view of one pixel in the
display device according to the Embodiment 1 when no voltage is
applied.
[0044] FIG. 6 is a schematic sectional view of one pixel in the
display device according to the Embodiment 1 when negative voltage
is applied.
[0045] FIG. 7 is a schematic sectional view of one pixel in a
display device according to the Modified Example 1.
[0046] FIG. 8 is a view of a drive circuit in the display device
according to the Modified Example 1.
[0047] FIG. 9 is a schematic sectional view of one pixel in a
display device according to the Embodiment 2.
[0048] FIG. 10 is a view of a drive circuit in the display device
according to the Embodiment 2.
[0049] FIG. 11 is a view of a drive circuit in a display device
according to the Modified Example 2.
[0050] FIG. 12 is a schematic sectional view of one pixel in a
display device according to the Embodiment 3 when no voltage is
applied.
[0051] FIG. 13 is a schematic sectional view of one pixel in the
display device according to the Embodiment 3 when negative voltage
is applied.
[0052] FIG. 14 is a view of a drive circuit in the display device
according to the Embodiment 3.
[0053] FIG. 15 is a schematic sectional view of one pixel in a
display device according to the Modified Example 3.
[0054] FIG. 16 is a view of a drive circuit in the display device
according to the Modified Example 3.
[0055] FIG. 17 is a schematic sectional view of one pixel in a
display device according to the Embodiment 4 when no voltage is
applied.
[0056] FIG. 18 is a schematic sectional view of one pixel in the
display device according to the Embodiment 4 when negative voltage
is applied.
[0057] FIG. 19 is a view of a drive circuit in the display device
according to the Embodiment 4.
[0058] FIG. 20 is a view of a drive circuit in a display device
according to the Modified Example 4-1.
[0059] FIG. 21 is a view of a drive circuit in a display device
according to the Modified Example 4-2.
[0060] FIG. 22 is a schematic sectional view of one pixel in a
display device according to the Embodiment 5.
[0061] FIG. 23 is a view of a drive circuit in the display device
according to the Embodiment 5.
[0062] FIG. 24 is a view of a drive circuit in a display device
according to the Modified Example 5-1.
[0063] FIG. 25 is a view of a drive circuit in a display device
according to the Modified Example 5-2.
[0064] FIG. 26 is a view of a drive circuit in a display device
according to the Modified Example 5-3.
[0065] FIG. 27 is a schematic sectional view of one pixel in a
display device according to the Embodiment 6.
[0066] FIG. 28 is a view of a drive circuit in the display device
according to the Embodiment 6.
[0067] FIG. 29 is a view of a drive circuit in a display device
according to the Modified Example 6-1.
[0068] FIG. 30 is a view of a drive circuit in a display device
according to the Modified Example 6-2.
[0069] FIG. 31 is a schematic sectional view of one pixel in a
display device according to the Embodiment 7 when no voltage is
applied.
[0070] FIG. 32 is a schematic sectional view of one pixel in the
display device according to the Embodiment 7 when negative voltage
is applied.
[0071] FIG. 33 is a schematic sectional view of one pixel in a
display device according to the Embodiment 8.
[0072] FIG. 34 is a schematic sectional view of one pixel in a
display device according to the Embodiment 9 when no voltage is
applied.
[0073] FIG. 35 is a schematic sectional view of one pixel in the
display device according to the Embodiment 9 when negative voltage
is applied.
[0074] FIG. 36 illustrates an example of a first slit and a second
slit in a display device according to the Embodiment 10.
DESCRIPTION OF EMBODIMENTS
[0075] The embodiments of the present invention will be described
in more detail referring to the drawings. However, the present
invention is not limited to these embodiments.
Embodiment 1
[0076] FIG. 1 is a schematic sectional view of one pixel in a
display device according to the Embodiment 1. FIG. 2 is a schematic
perspective view of one pixel of a first substrate which is
illustrated in FIG. 1. FIG. 3 is a schematic perspective view of
one pixel of a second substrate which is illustrated in FIG. 1. The
symbols "A" and "B" are common in FIGS. 1 to 3. FIG. 4 is a view of
a drive circuit in the display device according to the Embodiment
1.
[0077] As illustrated in FIG. 1, the display device according to
the Embodiment 1 includes a first substrate 10, a second substrate
20, and a backlight unit 30 in the stated order from the viewing
surface side towards the back surface side. The first substrate 10
includes a shutter (first shutter) 12. The second substrate 20
includes a shutter (second shutter) 22. The shutter 12 is movable.
During a non-display state, the shutter 12 overlaps a slit of the
shutter 22 and shields light which is emitted from the backlight
unit 30. During a display state, a slit of the shutter 12 overlaps
the slit of the shutter 22. Thus light emitted from the backlight
unit 30 passes through each of slits and outgoes as display
light.
[0078] As illustrated in FIGS. 1 and 2, the first substrate 10
includes a transparent substrate 11, the shutter (first shutter)
12, a first electrode 13, and a plurality of supports 14 which
support the shutter 12. The shutter 12 includes a plurality of
slits (each slit constitutes the first slit) 12a therein. The
periphery of the shutter 12 in a plan view is in a square
(rectangular) shape.
[0079] In square planar shutter 12, one end on a side which is
parallel with the longitudinal direction of the slit 12a is joined
to two supports 14a and 14b via a first elastic body (a spring) 15.
The other end on a side which is parallel with the longitudinal
direction of the slit 12a in the shutter 12 is joined to a support
14c via a second elastic body (a spring) 16. The shutter 12 is
reciprocatively movable in a horizontal direction with the aid of
expansion and contraction of the first elastic body 15 and the
second elastic body 16. The first electrode 13 is connected to a
power source 1 in the drive circuit. The first electrode 13 is
electrically isolated from the shutter 12. The support functions as
a second electrode 14 in the Embodiment 1. The second electrode 14
is electrically connected to the power source 1 in the drive
circuit via a charge electrode 9 and a rectifier circuit 17.
[0080] In FIG. 2, the support 14c, which is installed on the side
opposite to the first electrode via the shutter, is used as the
second electrode. Examples of materials for the second electrode 14
include aluminum (Al) and tungsten (W). Copper (Cu) or silver (Ag),
which has low electrical resistance, may also be suitably used.
[0081] The shutter 12 is positively or negatively charged. For
example, an electret may be used as the shutter 12. Electretization
may be performed using, for example, corona discharge. Examples of
the dielectric materials suitable for electretization include
polymer materials such as Teflon (Registered trademark),
polypropylene, and Mylar, and silicon oxide materials such as TEOS
(Tetra Ethylene Oxy Silane) and SiOF (Fluorine-doped Silicon
Oxide).
[0082] The shutter 12 may be made of a light shielding material, or
dispersion of a light shielding ingredient, such as resinous BM, in
a transparent material. When the shutter 12 has light shielding
property, the transmittance of light emitted from the backlight
unit 30 can be controlled.
[0083] The first elastic body 15 and the second elastic body 16 are
not limited in shape as long as they are elastic. The first elastic
body 15 and the second elastic body 16 may be made of an
electroconductive material, or a dielectric material. Since the
both ends of the shutter 12 are fixed via elastic bodies, slid
shutter 12 can return to the original position by a restoring force
of the elastic bodies, as will be described later.
[0084] The first electrode 13 is connected to a source driver of
the drive circuit. Positive or negative electrical potential is
supplied to the first electrode 13 from the power source 1. Thus,
Coulomb's force is generated between the first electrode 13 and
negatively-charged shutter 12. The shutter 12 can be moved
parallelly in a horizontal direction by the generated Coulomb's
force. Examples of materials for the first electrode 13 include,
similarly to the second electrode 14, aluminum (Al) and tungsten
(W). Copper (Cu) or silver (Ag), which has low electrical
resistance, may also be suitably used.
[0085] As illustrated in FIGS. 1 and 3, the second substrate 20
includes a transparent substrate 21 and the shutter (second
shutter) 22. The shutter 22 includes a plurality of slits (each
slit constitutes the second slit) 22a therein.
[0086] The shutter 22 may be made of a light shielding material, or
dispersion of a light shielding ingredient, such as resinous BM, in
a transparent material, similarly to the shutter 12.
[0087] At four corners of a region (square) corresponding to one
pixel of the second substrate, spacers 23 for separating the
shutter 12 and the shutter 22 at given intervals are arranged.
[0088] The backlight unit 30 includes optical parts such as a light
source, a light guide plate, and an optical sheet. The light source
may suitably be one which can emit inherent light such as red,
green, or blue light. Such light source enables highly efficient
utilization of light because the color display can be performed
even without color filters. Examples of the light source which can
emit inherent light such as red, green, or blue light include light
emitting diodes (LEDs). A combination of a white LED with a given
color filter which is stacked on the white LED may also be used as
an alternative. Other examples of light sources include a cold
cathode fluorescent lamp (CCFL). When CCFL is used as a light
source, color filters are necessary.
[0089] Now, a drive circuit in the display device according to the
Embodiment 1 is described referring to FIG. 4. As illustrated in
FIG. 4, the power source 1 is connected to a display controlling
circuit 3 in the display device of the Embodiment 1. The display
controlling circuit 3 is connected to a source driver 2 and a gate
driver 4. A series of circuits to be used for display control, such
as the power source 1, the display controlling circuit 3, the
source driver 2, and the gate driver 4 correspond to the "drive
circuit" according to the present invention. A plurality of source
wirings 5 are drawn from the source driver 2. A plurality of gate
wirings 6 are drawn from the gate driver 4. The source wirings 5
and the gate wirings 6 extend crosswise with each other. A region
surrounded by the source wirings 5 and the gate wirings 6 defines
one pixel. A TFT 7 is installed at each of intersections of source
wirings 5 and gate wirings 6. A drain wiring 8 is drawn from the
TFT 7. The drain wiring 8 is connected to the first electrode 13.
The second electrode 14 provided for each pixel is connected to the
charge electrode 9 which is common to all the pixels, and further
connected to the power source 1 via the rectifier circuit 17.
[0090] The rectifier circuit 17 is a circuit which includes a
commutator (a diode, for example). The rectifier circuit 17
installed between the second electrode 14 and the power source 1
enables an efficient supply of the electromotive force from the
second electrode 14 to the power source 1.
[0091] The above configuration of the circuit enables utilization
of an electromotive force which is generated by the movement of the
shutter 12, used for a part of the power source 1.
[0092] Materials for various parts and method of producing them are
described below.
[0093] The transparent substrates 11 and 21 are supporting
substrates. It is suitable that they are made of a transparent
insulating material such as glass and plastics.
[0094] The source wiring 5, the gate wiring 6, an electrode in the
TFT 7, and the charge electrode 9 may be produced, for example, by
sputtering a metal such as titanium (Ti), chromium (Cr), aluminum
(Al), and molybdenum (Mo), or alloy thereof to form a film in a
single layer or multilayers, and then patterning the film using,
for example, a photolithographic method.
[0095] The shutter 12, the first electrode 13, the second electrode
14, the first elastic body 15, and the second elastic body 16 may
be produced from the corresponding raw materials by an MEMS
technique.
[0096] A display device according to the application is completed
by first bonding the first substrate 10 and the second substrate 20
in which various parts are mounted, then packaging a gate driver, a
source driver, a display controlling circuit, and the like, and
finally combining a backlight unit.
[0097] Now, the driving process of the display device according to
the Embodiment 1 is described referring to FIGS. 5 and 6. FIGS. 5
and 6 are both schematic sectional views of one pixel in the
display device according to the Embodiment 1. FIG. 5 illustrates a
state when no voltage is applied. FIG. 6 illustrates a state when
negative voltage is applied.
[0098] When no voltage is applied, the slit 12a completely overlaps
the slit 22a as illustrated in FIG. 5. Light emitted from the
backlight unit 30 passes through the thus-overlapped slits 12a and
22a. As a result, the gray scale of the pixel shows a display state
of the highest brightness (white color is displayed).
[0099] On the contrary, when negative electrical potential is
supplied to the first electrode 13, Coulomb's force (repulsive
force) is generated between the first electrode 13 and the shutter
12 as illustrated in FIG. 6. Then, as illustrated in FIG. 6, the
shutter 12 slides away from the first electrode 13 in a horizontal
direction (left direction in FIG. 6). The first elastic body 15
extends by being pulled by the shutter 12. When the shutter 12
completely overlaps the slit 22a, the shutter 12 shields light
emitted from the backlight unit 30. As a result, the gray scale of
the pixel shows a display state of the lowest brightness (black
color is displayed).
[0100] When the shutter 12 slides in a left direction, the second
electrode 14, which doubles a support for the shutter 12,
approaches the shutter 12, and electrostatic induction is caused.
The second electrode 14 is then charged reversely to the polarity
of the shutter 12. In an embodiment as illustrated in FIG. 6, the
shutter 12 is negatively charged. Therefore, the second electrode
14 is positively charged.
[0101] Then, when the polarity of the electric potential which is
supplied to the first electrode 13 is switched, the shutter 12
returns to the original position by the restoring force of the
first elastic body 15.
[0102] The amount of the electric charge on the second electrode 14
changes as the distance between the shutter 12 and the second
electrode 14 varies, and thus electric current flows into the
charge electrode 9. The charge electrode 9 is connected to the
power source 1 in the drive circuit via the rectifier circuit 17 or
the like. Thus, the electromotive force generated can be used for a
part of the power source in the drive circuit.
[0103] The gray scale in the MEMS display is realized by
controlling the transmittance of light based on the degree of
overlap between the shutter 12 and the slit 22a, or by controlling
the transmittance per unit time of light outgoing from the
backlight by sliding the shutter 12 at a high speed. In the
Embodiment 1, the gray scale may be realized by positively charging
the shutter 12, and supplying positive electrical potential to the
first electrode.
[0104] A modified example of the Embodiment 1 in which the second
electrode is connected to a light source (Modified Example 1) is
now described as an example. FIG. 7 is a schematic sectional view
of one pixel in a display device according to the Modified Example
1. FIG. 8 is a view of a drive circuit in the display device
according to the Modified Example 1. As illustrated in FIGS. 7 and
8, the second electrode 14 is connected to a light source 40 in the
backlight unit via the charge electrode 9 and the rectifier circuit
17. In the Modified Example 1, electromotive force which is
generated by the movement of the first shutter can be used for a
part of the light source.
[0105] Thus, in the Embodiment 1, the shutter 12 slides side to
side as illustrated in FIGS. 5 and 6 in response to the switch of
the polarity of the electric potential which is supplied to the
first electrode, and therefore displaying and power generation can
be performed simultaneously. The electromotive force generated can
be used for a part of the power source in the drive circuit and/or
for a part of the light source. The power consumption can therefore
be reduced as a whole display device.
Embodiment 2
[0106] In the Embodiment 2, an external battery is installed. The
second electrode and the external battery are connected in series,
and the external battery is a secondary battery. Other than these
features, the Embodiment 2 is the same as the Embodiment 1. FIG. 9
is a schematic sectional view of one pixel in a display device
according to the Embodiment 2. FIG. 10 is a view of a drive circuit
in the display device according to the Embodiment 2.
[0107] As illustrated in FIGS. 9 and 10, the second electrode 14,
the charge electrode 9, the rectifier circuit 17, an external
battery 24, and the power source 1 are connected in series in the
stated order in the display device according to the Embodiment 2. A
secondary battery is used as the external battery 24. The type of
the secondary battery is not particularly limited.
[0108] Displaying by the display device according to the Embodiment
2 is performed by controlling the transmittance of light according
to the movement of the shutter 12, in the same manner as the
Embodiment 1. Electrical power is generated with the aid of the
movement of the shutter 12, contributing to lower power
consumption. Further in the display device according to the
Embodiment 2, the external battery can be charged with the aid of
the vibration from the outside of the display device (environmental
vibration) when the display device is turned off. Specifically, the
shutter 12 slides with the aid of environmental vibrations to cause
electrostatic induction. Electric charge is thereby supplied to the
external battery 24 via the second electrode 14, the charge
electrode 9, and the rectifier circuit 17. Thus, the external
battery 24 can be charged. The electric charge accumulated in the
external battery can be used as it is as an electromotive force in
the power source in the drive circuit when the display device is
turned on.
[0109] A modified example of the Embodiment 2 in which the second
electrode is connected to the light source (Modified Example 2) is
now described as an example. FIG. 11 is a view of a drive circuit
in a display device according to the Modified Example 2. As
illustrated in FIG. 11, the second electrode 14, the charge
electrode 9, the rectifier circuit 17, the external battery 24 and
the light source 40 in the backlight unit are connected in series
in the stated order in the Modified Example 2. The external battery
can be charged with the aid of the vibration from the outside of
the display device (environmental vibration) when the display
device is turned off. The electric charge accumulated in the
external battery can be used as it is as an electromotive force in
the light source when the display device is turned on.
[0110] Thus, in the Embodiment 2, the first shutter slides side to
side in response to the switch of the polarity of the electric
potential which is supplied to the first electrode, and therefore
displaying and power generation can be performed simultaneously, in
the same manner as the Embodiment 1. According to the Embodiment 2,
the external battery is charged in a non-display state, and
thus-charged electric power can be used for a part of the power
source in the drive circuit and/or for a part of the light source.
The power consumption can therefore be reduced as a whole display
device more efficiently.
Embodiment 3
[0111] The Embodiment 3 is the same as the Embodiment 1 except that
the second shutter doubles as the second electrode in place of the
support for a first shutter. FIGS. 12 and 13 are both schematic
sectional views of one pixel in a display device according to the
Embodiment 3. FIG. 12 illustrates a state when no voltage is
applied. FIG. 13 illustrates a state when negative voltage is
applied. FIG. 14 is a view of a drive circuit in the display device
according to the Embodiment 3. In the Embodiment 3, the second
shutter 22 is connected to the charge electrode 9 as illustrated in
FIGS. 12 to 14, and functions as a second electrode. The charge
electrode 9 is connected to the power source 1 in the drive circuit
via the rectifier circuit 17.
[0112] Now, the driving process of the display device according to
the Embodiment 3 is described referring to FIGS. 12 and 13. The
basic principle of display is the same as in the Embodiment 1. When
no voltage is applied, the slit 12a completely overlaps the slit
22a as illustrated in FIG. 12. Light emitted from the backlight
unit 30 passes through the thus-overlapped slits 12a and 22a. As a
result, the gray scale of the pixel shows a display state of the
highest brightness (white color is displayed).
[0113] On the contrary, when negative electrical potential is
supplied to the first electrode 13 from the power source 1,
Coulomb's force (repulsive force) is generated between the first
electrode 13 and the shutter 12 as illustrated in FIG. 13. Then,
the shutter 12 slides away from the first electrode 13 in a
horizontal direction (left direction in FIG. 13). The first elastic
body 15 extends by being pulled by the shutter 12. When the shutter
12 completely overlaps the slit 22a, the shutter 12 shields light
emitted from the backlight unit 30. As a result, the gray scale of
the pixel shows a display state of the lowest brightness (black
color is displayed).
[0114] When the shutter 12 slides in a left direction, the first
shutter 12 goes apart from the second electrode 22, which doubles
as the second shutter, and electrostatic induction is caused. Thus,
positive electric charge on the second electrode 22 decreases by
the electrostatic induction.
[0115] Then, when the polarity of the electric potential which is
supplied to the first electrode 13 is switched, the shutter 12
returns to the original position by the restoring force of the
first elastic body 15. The amount of the electric charge on the
second electrode 22 changes as the distance between the shutter 12
and the second electrode 22 varies, and thus electric current flows
into the charge electrode 9. The charge electrode 9 is connected to
the power source 1 in the drive circuit via the rectifier circuit
17. Thus, the electromotive force generated can be used for a part
of the power source in the drive circuit.
[0116] A modified example of the Embodiment 3 in which the second
electrode is connected to the light source (Modified Example 3) is
now described as an example. FIG. 15 is a schematic sectional view
of one pixel in a display device according to the Modified Example
3. FIG. 16 is a view of a drive circuit in the display device
according to the Modified Example 3. As illustrated in FIGS. 15 and
16, the second electrode 22 is connected to the light source 40 in
the backlight unit via the charge electrode 9 and the rectifier
circuit 17. In the Modified Example 4, the electromotive force
which is generated by the movement of the first shutter can be used
for a part of the light source.
[0117] Thus, in the Embodiment 3, the first shutter slides side to
side in response to the switch of the polarity of the electric
potential which is supplied to the first electrode, and therefore
displaying and power generation can be performed simultaneously, in
the same manner as the Embodiment 1. The electromotive force
generated can be used for a part of the power source in the drive
circuit and/or for a part of the light source. The power
consumption can therefore be reduced as a whole display device.
Embodiment 4
[0118] The Embodiment 4 is the same as the Embodiment 1 except that
a third electrode is installed in addition to the second electrode.
FIGS. 17 and 18 are both schematic sectional views of one pixel in
a display device according to the Embodiment 4. FIG. 17 illustrates
a state when no voltage is applied. FIG. 18 illustrates a state
when negative voltage is applied. FIG. 19 is a view of a drive
circuit in the display device according to the Embodiment 4.
[0119] In the Embodiment 4, the support 14c is connected to the
charge electrode 9 as illustrated in FIGS. 17 to 19, and functions
as the second electrode. The second shutter 22 is connected to a
charge electrode 19, and functions as a third electrode. The charge
electrode 9 is connected to the power source 1 in the drive circuit
via the rectifier circuit 17. The charge electrode 19 is connected
to the power source 1 in the drive circuit via a rectifier circuit
27.
[0120] Now, the driving process of the display device according to
the Embodiment 4 is described referring to FIGS. 17 and 18. The
basic principle of display is the same as in the Embodiment 1. When
no voltage is applied, the slit 12a completely overlaps the slit
22a as illustrated in FIG. 17. Light emitted from the backlight
unit 30 passes through the thus-overlapped slits 12a and 22a. As a
result, the gray scale of the pixel shows a display state of the
highest brightness (white color is displayed).
[0121] On the contrary, when negative electrical potential is
supplied to the first electrode 13 from the power source 1,
Coulomb's force (repulsive force) is generated between the first
electrode 13 and the shutter 12 as illustrated in FIG. 18. Then,
the shutter 12 slides away from the first electrode 13 in a
horizontal direction (left direction in FIG. 18). The first elastic
body 15 extends by being pulled by the shutter 12. When the shutter
12 completely overlaps the slit 22a, the shutter 12 shields light
emitted from the backlight unit 30. As a result, the gray scale of
the pixel shows a display state of the lowest brightness (black
color is displayed).
[0122] When the shutter 12 slides in a left direction, the second
electrode 14, which doubles a support for the shutter 12,
approaches the shutter 12, and electrostatic induction is caused.
The second electrode 14 is then charged reversely to the polarity
of the shutter 12. Also, the first shutter 12 goes apart from the
third electrode 22, which doubles as the second shutter, and
electrostatic induction is caused. Thus, positive electric charge
on the second electrode 22 decreases by the electrostatic
induction.
[0123] Then, when the polarity of the electric potential which is
supplied to the first electrode 13 is switched, the shutter 12
returns to the original position by the restoring force of the
first elastic body 15. The amount of the electric charge on the
second electrode 14 changes as the distance between the shutter 12
and the second electrode 14 varies, and thus electric current flows
into the charge electrode 9. The amount of the electric charge on
the second electrode 22 changes as the distance between the shutter
12 and the third electrode 22 varies, and thus electric current
flows into the charge electrode 19. The charge electrode 9 is
connected to the power source 1 in the drive circuit via the
rectifier circuit 17. The charge electrode 19 is connected to the
power source 1 in the drive circuit via the rectifier circuit 27.
Thus, the electromotive force generated can be used for a part of
the power source in the drive circuit.
[0124] A modified example of the Embodiment 4 in which the second
electrode and the third electrode are each connected to the light
source (Modified Example 4-1) is now described as an example. FIG.
20 is a view of a drive circuit in a display device according to
the Modified Example 4-1. As illustrated in FIG. 20, the second
electrode 14 is connected to the light source via the charge
electrode 9 and the rectifier circuit 17 in the Modified Example
4-1. The third electrode 22 is connected to the light source via
the charge electrode 19 and the rectifier circuit 27. In the
Modified Example 4-1, the electromotive force which is generated by
the movement of the first shutter can be used for a part of the
light source.
[0125] Another modified example of the Embodiment 4, in which
either one of the second electrode and the third electrode is
connected to the power source in the drive circuit, and the other
is connected to the light source (Modified Example 4-2), is now
described as an example. FIG. 21 is a view of a drive circuit in a
display device according to the Modified Example 4-2. As
illustrated in FIG. 21, the second electrode 14 is connected to the
power source 1 in the drive circuit via the charge electrode 9 and
the rectifier circuit 17 in the Modified Example 4-2. The third
electrode 22 is connected to the light source 40 via the charge
electrode 19 and the rectifier circuit 27. In the Modified Example
4-2, the second electrode 14 may be connected to the light source
40, and the third electrode 22 may be connected to the power source
1 in the drive circuit. In the Modified Example 4-2, the
electromotive force which is generated by the movement of the first
shutter can be used in the power source in the drive circuit and
the light source.
[0126] Thus in the Embodiment 4, the shutter 12 slides side to
side, as illustrated in FIGS. 17 and 18, in response to the switch
of the polarity of the electric potential which is supplied to the
first electrode, and therefore displaying and power generation can
be performed simultaneously. Further in the Embodiment 4, both of
the second electrode and the third electrode can supply a new
electromotive force to the power source in the drive circuit and/or
the light source by utilizing the transfer of electric charges
which is caused by the movement of the first shutter. The power
consumption can therefore be more reduced as a whole power
generation display device.
Embodiment 5
[0127] The Embodiment 5 is the same as the Embodiment 4 except that
one external battery is installed. FIG. 22 is a schematic sectional
view of one pixel in a display device according to the Embodiment
5. FIG. 23 is a view of a drive circuit in the display device
according to the Embodiment 5. As illustrated in FIGS. 22 and 23,
the second electrode 14 and the third electrode 22 are connected in
parallel. The second electrode 14 is connected to the external
battery 24 in series via the charge electrode 9 and the rectifier
circuit 17. The third electrode 22 is connected to the same
external battery 24 in series via the charge electrode 19 and the
rectifier circuit 27. The external battery 24 is connected to the
power source 1 in the drive circuit. A secondary battery is used as
the external battery 24. The type of the secondary battery is not
particularly limited.
[0128] The configuration as illustrated in FIGS. 22 and 23 enables
utilization of the electromotive force which is generated by the
movement of the first shutter, used for a part of the power source
in the drive circuit. The external battery can be charged with the
aid of the vibration from the outside of the display device
(environmental vibration) when the display device is turned off.
The electric charge accumulated in the external battery can be used
as it is as an electromotive force in the power source in the drive
circuit when the display device is turned on.
[0129] A modified example of the Embodiment 5, in which either one
of the second electrode and the third electrode is connected to an
external battery in series (Modified Example 5-1), is now described
as an example. FIG. 24 is a view of a drive circuit in a display
device according to the Modified Example 5-1. As illustrated in
FIG. 24, the second electrode 14, the charge electrode 9, the
rectifier circuit 17, the external battery 24, and the power source
1 are connected in series in the stated order in the Modified
Example 5-1. The third electrode 22 is connected to the power
source 1 in the drive circuit not via the external battery 24. The
third electrode 22 and the external battery 24 may be connected in
series in the Modified Example 5-1. In the Modified Example 5-1,
the electromotive force which is generated by the movement of the
first shutter can be used for a part of the power source in the
drive circuit. The external battery can be charged with the aid of
the vibration from the outside of the display device (environmental
vibration) when the display device is turned off. The electric
charge accumulated in the external battery can be used as it is as
an electromotive force in the power source in the drive circuit
when the display device is turned on.
[0130] Another modified example of the Embodiment 5 in which the
second electrode and the third electrode are connected to the light
source (Modified Example 5-2) is now described as an example. FIG.
25 is a view of a drive circuit in a display device according to
the Modified Example 5-2. As illustrated in FIG. 25, the second
electrode 14 and the third electrode 22 are connected in parallel
in the Modified Example 5-2. The second electrode 14 is connected
to the external battery 24 in series via the charge electrode 9 and
the rectifier circuit 17. The third electrode 22 is connected to
the same external battery 24 in series via the charge electrode 19
and the rectifier circuit 27. The external battery 24 is connected
to the light source 40. In the Modified Example 5-2, the
electromotive force which is generated by the movement of the first
shutter can be used for a part of the light source. The external
battery can be charged with the aid of the vibration from the
outside of the display device (environmental vibration) when the
display device is turned off. The electric charge accumulated in
the external battery can be used as it is as an electromotive force
in the light source when the display device is turned on.
[0131] Another modified example of the Embodiment 5, in which
either one of the second electrode and the third electrode is
connected to the power source in the drive circuit, and the other
is connected to the light source (Modified Example 5-3), is now
described as an example. FIG. 26 is a view of a drive circuit in a
display device according to the Modified Example 5-3. As
illustrated in FIG. 26, the second electrode 14 is connected to the
power source 1 in the drive circuit via the charge electrode 9, the
rectifier circuit 17 and the external battery 24 in the Modified
Example 5-3. The third electrode 22 is connected to the light
source 40 via the charge electrode 19 and the rectifier circuit 27.
In the Modified Example 5-3, the third electrode may be connected
to the external battery. The second electrode 14 may be connected
to the light source 40, and the third electrode 22 may be connected
to the power source 1 in the drive circuit. In the Modified Example
5-3, the electromotive force which is generated by the movement of
the first shutter can be used for a part of the power source in the
drive circuit and the light source. The external battery can be
charged with the aid of the vibration from the outside of the
display device (environmental vibration) when the display device is
turned off. The electric charge accumulated in the external battery
can be used as it is as an electromotive force in the power source
in the drive circuit and the light source when the display device
is turned on.
[0132] Thus, in the Embodiment 5, the first shutter slides side to
side in response to the switch of the polarity of the electric
potential which is supplied to the first electrode, and therefore
displaying and power generation can be performed simultaneously, in
the same manner as the Embodiment 4. The electromotive force
generated can be used for a part of the power source in the drive
circuit and/or for a part of the light source. The power
consumption can therefore be reduced as a whole display device.
Embodiment 6
[0133] The Embodiment 6 is the same as the Embodiment 4 except that
two external batteries (one is referred to as a first external
battery, and the other is referred to as a second external battery)
are installed. FIG. 27 is a schematic sectional view of one pixel
in a display device according to the Embodiment 6. FIG. 28 is a
view of a drive circuit in the display device according to the
Embodiment 6. As illustrated in FIGS. 27 and 28, the second
electrode 14 and the first external battery 24 are connected in
series. The third electrode 22 and the second external battery 34
are connected in series. The first external battery 24 and the
second external battery 34 are connected in parallel. The second
electrode 14, the charge electrode 9, the rectifier circuit 17, the
first external battery 24, and the power source 1 are connected in
series in the stated order. The third electrode 22, the charge
electrode 9, the rectifier circuit 27, the second external battery
34, and the power source 1 are connected in series in the stated
order.
[0134] The configuration as illustrated in FIGS. 27 and 28 enables
utilization of the electromotive force which is generated by the
movement of the first shutter, used for a part of the power source
in the drive circuit. The external battery can be charged with the
aid of the vibration from the outside of the display device
(environmental vibration) when the display device is turned off.
The electric charge accumulated in the external battery can be used
as it is as an electromotive force in the power source in the drive
circuit when the display device is turned on.
[0135] A modified example of the Embodiment 6 in which the second
electrode and the third electrode are connected to the light source
(Modified Example 6-1) is now described as an example. FIG. 29 is a
view of a drive circuit in a display device according to the
Modified Example 6-1. As illustrated in FIG. 29, the second
electrode 14, the charge electrode 9, the rectifier circuit 17, and
the first external battery 24 are connected in series in the stated
order in the Modified Example 6-1. The third electrode 22, the
charge electrode 9, the rectifier circuit 27, and the second
external battery are connected in series in the stated order. The
first external battery 24 and the second external battery 34 are
connected in parallel, and both of them are connected to the light
source 40. In the Modified Example 6-1, the electromotive force
which is generated by the movement of the first shutter can be used
for the light source in the drive circuit. The external battery can
be charged with the aid of the vibration from the outside of the
display device (environmental vibration) when the display device is
turned off. The electric charge accumulated in the external battery
can be used as it is as an electromotive force in the light source
when the display device is turned on.
[0136] Another modified example of the Embodiment 6, in which
either one of the second electrode and the third electrode is
connected to the power source in the drive circuit, and the other
is connected to the light source (Modified Example 6-2), is now
described as an example. FIG. 30 is a view of a drive circuit in a
display device according to the Modified Example 6-2. As
illustrated in FIG. 30, the second electrode 14 is connected to the
power source 1 in the drive circuit via the charge electrode 9, the
rectifier circuit 17, and the first external battery 24 in the
Modified Example 6-2. The third electrode 22 is connected to the
light source 40 via the charge electrode 19, the rectifier circuit
27, and the second external battery 34. In the Modified Example
6-2, the second electrode 14 may be connected to the light source
40, and the third electrode 22 may be connected to the power source
1 in the drive circuit. In the Modified Example 6-2, the
electromotive force which is generated by the movement of the first
shutter can be used for a part of the power source in the drive
circuit and the light source. The external battery can be charged
with the aid of the vibration from the outside of the display
device (environmental vibration) when the display device is turned
off. The electric charge accumulated in the external battery can be
used as it is as an electromotive force in the power source in the
drive circuit or the light source when the display device is turned
on.
[0137] Thus, in the Embodiment 6, the first shutter slides side to
side in response to the switch of the polarity of the electric
potential which is supplied to the first electrode, and therefore
displaying and power generation can be performed simultaneously, in
the same manner as the Embodiment 4. The electromotive force
generated can be used for a part of the power source in the drive
circuit and/or for a part of the light source. The power
consumption can therefore be reduced as a whole display device.
Embodiment 7
[0138] The Embodiment 7 is the same as the Embodiment 1 except that
the positions of the first shutter and the second shutter are
different when black or white color is displayed. FIGS. 31 and 32
are both schematic sectional views of one pixel in a display device
according to the Embodiment 7. FIG. 31 illustrates a state when no
voltage is applied. FIG. 32 illustrates a state when negative
voltage is applied.
[0139] When no voltage is applied, the shutter 12 in the display
device according to the Embodiment 7 completely overlaps the slit
22a as illustrated in FIG. 31. Then, the shutter 12 shields light
emitted from the backlight unit 30. As a result, the gray scale of
the pixel shows a display state of the lowest brightness (black
color is displayed).
[0140] On the contrary, when negative electrical potential is
supplied to the first electrode 13, Coulomb's force (repulsive
force) is generated between the first electrode 13 and the shutter
12 as illustrated in FIG. 32. Then, as illustrated in FIG. 32, the
shutter 12 slides away from the first electrode 13 in a horizontal
direction (left direction in FIG. 32). The first elastic body 15
extends by being pulled by the shutter 12. When the slit 12a
completely overlaps the slit 22a, light emitted from the backlight
unit 30 passes through the thus-overlapped slits 12a and 22a. As a
result, the gray scale of the pixel shows a display state of the
highest brightness (white color is displayed).
[0141] The gray scale is realized by controlling the transmittance
of light based on the degree of overlap between the shutter 12 and
the slit 22a, or by controlling the transmittance per unit time of
light outgoing from the backlight by sliding the shutter 12 at a
high speed, in the same manner as the Embodiment 1.
[0142] Thus, in the Embodiment 7, the shutter 12 slides side to
side, as illustrated in FIGS. 31 and 32, in response to the switch
of the polarity of the electric potential which is supplied to the
first electrode, and therefore displaying and power generation can
be performed simultaneously. The electromotive force generated can
be used for a part of the power source in the drive circuit. The
power consumption can therefore be reduced as a whole display
device.
Embodiment 8
[0143] The Embodiment 8 is the same as the Embodiment 1 except that
the arrangement of the first substrate, the second substrate, and
the backlight unit is different. FIG. 33 is a schematic sectional
view of one pixel in a display device according to the Embodiment
8. As illustrated in FIG. 33, the display device according to the
Embodiment 8 includes the second substrate 20, the first substrate
10, and the backlight unit 30 in the stated order from the viewing
surface side towards the back surface side.
[0144] In the Embodiment 8, the first shutter slides side to side
in response to the switch of the polarity of the electric potential
which is supplied to the first electrode, and therefore displaying
and power generation can be performed simultaneously, in the same
manner as the Embodiment 1. The electromotive force generated can
be used for a part of the power source in the drive circuit. The
power consumption can therefore be reduced as a whole display
device.
Embodiment 9
[0145] The Embodiment 9 is the same as the Embodiment 1 except that
the first slit is positively charged, and the first slit slides
side to side by an attractive force between the first slit and the
first electrode. FIGS. 34 and 35 are both schematic sectional views
of one pixel in a display device according to the Embodiment 9.
FIG. 34 illustrates a state when no voltage is applied. FIG. 35
illustrates a state when negative voltage is applied.
[0146] When no voltage is applied, the slit 12a completely overlaps
the slit 22a as illustrated in FIG. 34. Light emitted from the
backlight unit 30 passes through the thus-overlapped slits 12a and
22a. As a result, the gray scale of the pixel shows a display state
of the highest brightness (white color is displayed). In the
Embodiment 9, the first slit is positively charged.
[0147] On the contrary, when negative electrical potential is
supplied to the first electrode 13, Coulomb's force (attractive
force) is generated between the first electrode 13 and the shutter
12 as illustrated in FIG. 35. Then, as illustrated in FIG. 35, the
shutter 12 slides to approach the first electrode 13 in a
horizontal direction (right direction in FIG. 35). Then, the second
elastic body 16 extends by being pulled by the shutter 12. When the
shutter 12 completely overlaps the slit 22a, the shutter 12 shields
light emitted from the backlight unit 30. As a result, the gray
scale of the pixel shows a display state of the lowest brightness
(black color is displayed).
[0148] When the shutter 12 slides in a right direction, the shutter
12 goes apart from the second electrode 14, which doubles as a
support for the shutter 12, and electrostatic induction is caused.
Thus, negative electric charge on the second electrode 22 decreases
by the electrostatic induction.
[0149] Then, when the polarity of the electric potential which is
supplied to the first electrode 13 is switched, the shutter 12
returns to the original position by the restoring force of the
second elastic body 16.
[0150] The amount of the electric charge on the second electrode 14
changes as the distance between the shutter 12 and the second
electrode 14 varies, and thus electric current flows into the
charge electrode 9. The charge electrode 9 is connected to the
power source 1 in the drive circuit via the rectifier circuit 17 or
the like. Thus, the electromotive force generated can be used for a
part of the power source in the drive circuit.
[0151] In the Embodiment 9, the first shutter slides side to side
in response to the switch of the polarity of the electric potential
which is supplied to the first electrode, and therefore displaying
and power generation can be performed simultaneously, in the same
manner as the Embodiment 1. The electromotive force generated can
be used for a part of the power source in the drive circuit. The
power consumption can therefore be reduced as a whole display
device.
Embodiment 10
[0152] The Embodiment 10 is the same as the Embodiment 1 except
that the shapes of the first slit and the second slit are
different. FIG. 36 illustrates an example of a first slit and a
second slit in a display device according to the Embodiment 10.
[0153] As illustrated in FIG. 36, one first slit 12a is in a square
shape in the display device according to the Embodiment 10. A
plurality of the slits 12a arrange in one direction to form one
line. A plurality of lines each of which are the same as the above
one line of the slits 12a are disposed, and the plurality of lines
are arranged in the direction perpendicular to the longitudinal
direction of the one line in parallel with each other. One line of
the plurality of lines corresponds to the rectangular slit 12a in
the Embodiment 1, and displaying is performed by transmitting or
shielding light emitted from the backlight unit.
[0154] The second slit 22a has the same configuration as the first
slit 12a, and thus, one second slit 22a is in a square shape. A
plurality of the slits 22a arrange in one direction to form one
line. A plurality of lines each of which are the same as the above
one line of the slits 22a are disposed, and the plurality of lines
are arranged in the direction perpendicular to the longitudinal
direction of the one line in parallel with each other. One line of
the plurality of lines corresponds to the rectangular slit 22a in
the Embodiment 1, and displaying is performed by transmitting or
shielding light emitted from the backlight unit.
[0155] In the Embodiment 10, both the first slit and the second
slit may have a structure in which each slit is in a square shape.
It is also possible for the first slit and the second slit to have
a structure in which each slit of either one of the first slit and
the second slit is in a square shape, and that of the other is in a
rectangular shape such as described in the Embodiment 1.
[0156] In the Embodiment 10, the first shutter slides side to side
in response to the switch of the polarity of the electric potential
which is supplied to the first electrode, and therefore displaying
and power generation can be performed simultaneously, in the same
manner as the Embodiment 1. The electromotive force generated can
be used for a part of the power source in the drive circuit. The
power consumption can therefore be reduced as a whole display
device.
[0157] Thus, the Embodiments 1 to 10 and modified examples thereof
were described as above. The Embodiments 1 to 10 and modified
examples thereof may be appropriately combined as long as they are
compatible.
REFERENCE SIGNS LIST
[0158] 1: Power source in the drive circuit [0159] 2: Source driver
[0160] 3: Display controlling circuit [0161] 4: Gate driver [0162]
5: Source wiring [0163] 6: Gate wiring [0164] 7: TFT [0165] 8:
Drain wiring [0166] 9, 19: Charge electrode [0167] 10: First
substrate [0168] 11, 21: Transparent substrate [0169] 12: First
shutter [0170] 12a: First slit [0171] 13: First electrode [0172]
14: Second electrode [0173] 14a, 14b, 14c: Support [0174] 15: First
elastic body [0175] 16: Second elastic body [0176] 17, 27:
Rectifier circuit [0177] 20: Second substrate [0178] 22: Second
shutter, third electrode [0179] 22a: Second slit [0180] 23: Spacer
[0181] 24, 34: External battery [0182] 30: Backlight unit [0183]
40: Light source
* * * * *